October 22nd, 2014

Quick Comparison of Popular 6.5mm Rifle Cartridges

6.5 Cartridge Guide Eben Brown EABco e. arthur brown 260 rem 6.5x47 6.5 creedmoor 6.5x55
Chart created with Ammoguide’s Visual Comparison Tool. Visit Ammoguide.com to learn more.

by Eben Brown, EABCO.com, (E. Arthur Brown Co. Inc.)
The current popularity of 6.5mm cartridges in the USA has been a long time in coming. I won’t go into my opinions on why it took so long to catch on. The important thing is that it finally HAS caught on and we’re now so fortunate to have a wide selection of 6.5mm cartridges to choose from!

6.5mm Grendel – Developed by Alexander Arms for the AR15 and military M4 family of rifles. The Grendel fits the dimensional and functional requirements of these rifles while delivering better lethality and downrange performance. There are now similar cartridges from other rifle companies. We chamber for the Les Baer “264 LBC-AR”. Designed for velocities of 2400-2500 fps with 123gr bullets, it shoots the 140-grainers at about 2000 fps (for comparison purposes).

6.5mm BRM – Developed by E. Arthur Brown Company to give “Big Game Performance to Small Framed Rifles” — namely our Model 97D Rifle, TC Contender, and TC Encore. Velocities of 2400-2500 fps with 140gr bullets puts it just under the original 6.5×55 Swede performance.

6.5mm x 47 Lapua – Developed by Lapua specifically for international 300m shooting competitions (with some interest in long-range benchrest as well). Case capacity, body taper, shoulder angle, and small rifle primer are all features requested by top international shooters. You can expect velocities of 2500-2600+ with 140 gr bullets.

6.5mm Creedmoor – Developed by Hornady and Creedmoor Sports, the 6.5mm Creedmoor is designed for efficiency and function. Its shape reaches high velocities while maintaining standard .308 Winchester pressures and its overall length fits well with .308 Win length magazines. You can expect velocities of 2600-2700+ fps with 140gr bullets.

.260 Remington – Developed by Remington to compete with the 6.5mmx55 Swedish Mauser that was (finally) gaining popularity in 1996. By necking down the 7mm-08 Remington to 6.5mm (.264 cal), the .260 Remington was created. It fit the same short-action [receivers] that fit .308 Win, .243 Win, 7mm-08 Rem, etc. You can expect velocities of 2600-2700 fps with 140gr bullets in the 260 .Remington.

[Editor's Note: In the .260 Rem, try the Lapua 120gr Scenar-Ls and/or Berger 130gr VLDs for great accuracy and impressive speeds well over 2900 fps.]

6.5mm x 55 Swedish Mauser – This was the cartridge that started the 6.5mm craze in the USA. It is famous for having mild recoil, deadly lethality on even the biggest game animals, and superb accuracy potential. Original ballistics were in the 2500 fps range with 140gr bullets. Nowadays handloaders get 2600-2700+ fps.

[Editor's Note: Tor from Scandinavia offers this bit of 6.5x55mm history: "Contrary to common belief, the 6.5×55 was not developed by Mauser, but was constructed by a joint Norwegian and Swedish military commission in 1891 and introduced as the standard military cartridge in both countries in 1894. Sweden chose to use the cartridge in a Mauser-based rifle, while Norway used the cartridge in the Krag rifles. This led to two different cartridges the 6.5×55 Krag and 6.5×55 Mauser -- the only real difference being safe operating pressure."]

6.5-284 Norma — This comes from necking the .284 Winchester down to .264 caliber. Norma standardized it for commercial ammo sales. The 6.5mm-284 was very popular for F-Class competition and High Power at 1,000 yards. However, many F-Class competitors have switched to the straight .284 Win for improved barrel life. 6.5-284 velocities run 3000-3100+ fps with 140gr bullets.

.264 Winchester Magnum – Developed by Winchester back in 1959, the .264 Win Mag never really caught on and may have delayed the ultimate acceptance of 6.5mm cartridges by US shooters (in my opinion). It missed the whole point and original advantage of 6.5 mm cartridges.

The Original 6.5mm Advantage
The special needs of long-range competition have skewed things a little. However the original advantages of 6.5mm cartridges — how deadly the 6.5mms are on game animals, how little recoil they produce, and how easy they are to shoot well — still hold true today.

6.5 Cartridge Guide Eben Brown EABco e. arthur brown 260 rem 6.5x47 6.5 creedmoor 6.5x55

Permalink - Articles, Bullets, Brass, Ammo 3 Comments »
October 22nd, 2014

Holy Benjamins! $200 Rebate on HK Pistols and MR Rifle

Two Hundred Bucks. A Pair of Benjamins. Now THAT’s a serious rebate. Save now with the HK Days Rebate Program. Here’s how it works. If you purchase a new, qualifying Heckler & Koch firearm, you will receive a Visa Card with $200.00 worth of built-in credit.

Heckler & Koch rebate Visa Card USP Mark 23 Pistol

Heckler & Koch USA is offering the $200 VISA card with a new HK firearm purchased from November 1, 2014 through December 31, 2014. The offer covers new HK firearm models: USP, P30, HK45, Mark 23 (shown below), and MR rifles. These are very fine firearms. This Editor has owned two HK USPs in .45 ACP. They were both rugged and extremely accurate — accurate as in being able to put an entire magazine into a quarter-sized hole at 10 yards.

Heckler & Koch rebate Visa Card USP Mark 23 Pistol

How to Get HK Days $200.00 Visa Card
NOTE: The eligible purchase period starts on November 1, 2014 (so you’ll have to wait at bit.) Retail customers need to complete a reply coupon and send it to Heckler & Koch along with a dated copy of their sales receipt. Coupon forms are available at most HK authorized dealers or can be downloaded at http://tiny.cc/HKDays. For more information, contact Heckler & Koch at 706-568-1906 ext. 6551, or send email to: promo [at] heckler-koch-us.com.

Heckler & Koch rebate Visa Card USP Mark 23 Pistol

Permalink Handguns, Hot Deals Post comment »
October 22nd, 2014

Storage Sacks for Firearms in Your Safe

Bore-Store Gun SacksOur take on Bore-Store Gun sleeves is simple: They work great, so buy them and use them — for ALL your valuable firearms.

These thick, synthetic-fleece sacks cushion your guns, preventing nicks and scratches. The breathable fabric wicks away moisture, and the fibers are coating with corrosion inhibitors. I personally use Bore-Stores for in-safe storage with all my guns, and I have never had one of my guns rust inside a Bore-Store, even when I lived a stone’s throw from the ocean.

Bore-Stores are offered in a wide range of sizes, so you can find something to fit everything from a Snub-nosed revolver to a 32″-barrelled 50 BMG. Rifle-size Bore Stores can be purchased for $12.00 – $21.00 from Brownells. For long F-Class or tactical rifles, we recommend the 10″x52″ Scoped Shotgun Bag, Brownells item 132-000-003. You can also order direct from the Bore-Store manufacturer, Big Spring Enterprises, www.BoreStores.com. Big Spring will also craft custom sizes on request.

Consider Military-Style, Triple-Layer Bags for Long-Term Storage
While we prefer Bore-Stores for regularly-used guns, if you have heirloom firearms that will be kept in storage for very long periods without seeing any use, you may want to grease them up and place them in the thin, but rugged three-layer storage bags sold by Brownells. The bags are made from a three-layer laminate of polyester, aluminum, and polyethylene film, with a shiny silver exterior. Though the laminate is thin, the Brownells storage bags are puncture-resistant, and have a 0% moisture transmission rating so moisture can’t get inside. These bags are also resistant to petroleum-based chemicals and they won’t break down even in contact with soil or moisture.

3-layer Brownells storage bagHere’s one VITAL bit of advice for using these bags. Be absolutely sure, before you seal up the bags, that your guns are DRY and that all metal surfaces have been coated with an effective anti-corrosive, such as BoeShield T9 or Eezox. Brownells’ storage bags are inexpensive. A three-pak of 12″x 60″ rifle sacks (item 083-055-003WB) costs just $22.99 — under eight bucks a gun. That’s cheap insurance for rifles and shotguns that may cost thousands of dollars.

Get Your Guns Out of Foam-lined Cases — They Are Rust Magnets
Just about the worst thing you can do in the winter (short of leaving your rifle outside in the rain) is to store firearms in tight, foam-padded cases. The foam in these cases actually collects and retains moisture from the air, acting as the perfect breeding ground for rust.

Foam-lined hard caseRemember, those plastic-shelled cases with foam interiors are for transport, not for long-term storage. Don’t repeat the mistake of a wealthy gun collector I know. He stored four valuable Colt Single Action Army (SAA) revolvers in individual foam-padded cases, and locked these away in his gun safe. A year later, every one of his precious SAAs had rusted, some badly.

Permalink Gear Review, Tech Tip 9 Comments »
October 21st, 2014

IMR Introduces New Enduron Powders: 4166, 4451, 7977

IMR Hodgdon Enduron PowderIMR is bringing out a new series of advanced-formulation extruded powders. In 2015, IMR will introduce three (3) new Enduron powders: IMR 4166, IMR 4451, and IMR 7977. The new line of IMR Enduron powders feature small kernels for easy metering, plus a built-in copper fouling eliminator. IMR claims that Enduron powders are not sensitive to temperature changes. If this is true, these powders should prove popular, particularly IMR 4166 which seems to be in the Varget/Reloder 15 burn-rate range. With Varget so hard to find, if IMR 4166 proves accurate (and available) we might see many .308 Win shooters make the switch. IMR states that IMR 4166 is a “versatile, match grade propellant”. We’ve been quite pleased with IMR 8208 XBR as a Varget alternative. IMR 8208 XBR is accurate, clean-burning, and offers good velocity. Perhaps the new IMR 4166 will be as good or better.

When will Enduron powders appear on dealers’ shelves? Hodgdon Powder Co., distributors of Hodgdon, IMR, and Winchester powders, says that: “The new IMR Enduron™ Technology powders will be available at dealers in early 2015 in 1-pound and 8-pound containers.” For more information and Enduron LOAD DATA visit imrpowder.com or check the 2015 Hodgdon Annual Manual.

IMR’s press release provides these descriptions of the new Enduron propellants:

IMR 4166 is the first in the series of Enduron™ propellants. It’s a perfect burn speed for cartridges like the 308 Win/7.62mm NATO, 22-250 Remington, 257 Roberts and dozens more.

IMR 4451 Another new Enduron powder that gives top performance in the venerable .30-06, 270 Winchester, and 300 Winchester Short Magnum, to name just a few. This propellant is ideally suited for many mid-range burn speed cartridges.

IMR 7977 is the slowest burn rate Enduron Technology powder. It is a true magnum cartridge propellant with outstanding performance in such cartridges as the .300 Winchester Magnum, 7mm Remington Magnum, .338 Lapua and more.

IMR Hodgdon Enduron Powder

Permalink New Product, Reloading 5 Comments »
October 21st, 2014

Watch and Read: Chris Cheng and Kelly Bachand Explain I-594

Washington State Ballot Initiative 594, otherwise known as I-594, is bad news. This poorly-written proposed law puts dramatic restrictions on gun owners. I-594 could criminalize many traditional types of shooting activities (including training with shared firearms). I-594 is so sweeping and vague that law enforcement groups consider the initiative “unenforceable”. If you live in Washington State, you need to educate yourself about I-594. In this story, two of our shooter friends (and contributors to the Daily Bulletin) analyze I-594 and explain its flaws.

Kelly Bachand: Why is I-594 bad? I-594 is posing as a background check initiative, but that’s not what it is. I-594 limits the legal modes of recreational use by redefining a firearms transfer to include almost any time that a firearm changes hands, even if it’s just for demonstration purposes, a short-term loan, or a bona fide gift.

Top Shot’s Chris Cheng Reveals the Dark Side of I-594
If you believe in Second Amendment rights, you should watch this video. If you believe in gun rights and live in Washington state, you should make sure your friends, neighbors, and family members of voting age watch this video. Chris Cheng does a great job exposing the flaws of I-594:

Kelly Bachand I-594Kelly Bachand Analyzes Washington State Initiatives I-594 and I-591
Since I’m a licensed firearms dealer I’ve had to learn a lot about the law concerning firearms. It makes sense then that close friends have asked me about my position on I-594 and I-591 which are on the ballot in Washington. I’ve read the full text for both a few times. How will I vote? I will vote yes on I-591. I will vote no on I-594.

I opened up my voter’s pamphlet last night and I was incredibly surprised to find that in the Explanatory Statement from the WA Office of Attorney General, there is a statement that is simply untrue. It precedes both initiatives in the voter’s pamphlet and it reads “In Washington, a background check is only required to buy a pistol, and only if the seller is a firearms dealer.” That’s simply untrue. Every time I sell ANY firearm a background check is performed, background checks are not just done for handgun sales. Furthermore, handgun sales in WA require a secondary, redundant background check performed by local law enforcement [which is] reported to the WA DOL. S0, there are actually two background checks performed on a typical handgun sale.

Why is I-594 bad? I-594 is posing as a background check initiative, but that’s not what it is. Background checks are not bad, I-594 is bad because it’s not about background checks. If it was a well-written background check initiative that addressed actual issues with mental health and domestic violence documentation then there could actually be many firearms owners who supported it. Unfortunately, the largest impact on firearms that I-594 will have is to limit the legal modes of recreational use that are available to law abiding citizens. The things it purports to stop are already illegal so it won’t bother criminals at all that there is one more law they are breaking. I-594 limits the legal modes of recreational use by redefining a firearms transfer to include almost any time that a firearm changes hands, even if it’s just for demonstration purposes, a short term loan, or a bona fide gift.

Under I-594 I would no longer be able to borrow my friend’s new pistol to take to the range and test out before I buy one of my own; that would be a criminal act. Nor would I be able to lend my father-in-law a shotgun so that he could go shoot trap with his church group; that would be a criminal act. Why would I make such specific examples of what would be illegal under I-594? Those sorts of simple examples I gave are simple actions that many responsible firearms owners do regularly, and now they would be criminal. It’s already illegal to sell to a felon or anyone you even think may not be able to own a firearm. If I-594 is passed, it won’t bother criminals at all, they will still get firearms from black markets and through theft, but it will really bother those law0abiding citizens who enjoy even the simplest things like target shooting and introducing their friends to the same.

Why is I-591 better? I-591 says that WA State’s background check system will continue to be in line with the ATF’s regulations, the law at a federal/national level. The means background checks are still required for all firearms sales by dealers. It also means that law-abiding gun owners won’t be criminalized for typical recreational activities with firearms. I-591 also restates that confiscating firearms from a citizen by any government agency without due process is illegal. Is this already unlawful? Yes it is. It has been demonstrated, though, that in some states where initiatives like I-594 have passed (California for example) that the increased government oversight on law abiding citizens’ activities has created scenarios where firearms have been confiscated without due process.

Permalink - Articles, News Post comment »
October 21st, 2014

Shooting Skills: Reading the Wind When Hunting

Norway Hunting Snow

Thomas Haugland, a Shooters’ Forum member from Norway, is a long-range target shooter and hunter. He has created an interesting video showing how to gauge wind velocities by watching trees, grass, and other natural vegetation. The video commentary is in English, but the units of wind speed (and distance) are metric. Haugland explains: “This is not a full tutorial, but rather a short heads-up to make you draw the lines between the dots yourself”. Here are some conversions that will help when watching the video:

.5 m/s = 1.1 mph | 1 m/s = 2.2 mph | 2 m/s = 4.5 mph
3 m/s = 6.7 mph | 4 m/s = 8.9 mph | 5 m/s =11.2 mph

More Interesting Videos from Norway
There are many other interesting videos on Haugland’s YouTube Channel, including Game Stalking, Precision Reloading, and Tips on how to use a Mildot Reticle on a scope with MOA-based clicks.

Permalink - Videos, Hunting/Varminting, Shooting Skills 3 Comments »
October 20th, 2014

Timney Triggers Made with State-of-the-Art Automated Machinery

For years, Timney triggers have been popular drop-in upgrades for hunting rifles, rimfire rifles, and AR platform rifles. To meet the demand for its many trigger products, Timney Triggers has expanded its operation, adding state-of-the-art CNC machines and other high-end, automated equipment. A far cry from the dank gun factories of the 1950s and 1960s, Timney’s Arizona production center now resembles the squeaky-clean, ultra-modern facilities where electronics are assembled.

Today’s Timney factory is truly a miracle of computerized automation. Timney Triggers’ owner John Vehr states that it would take 60 or more trained machinists and metal-workers to produce as many triggers as can Timney’s modern machines. Timney does employ two dozen workers, but they are assigned tasks that the computerized machines can’t do as well or better.

If you want to see how Timney triggers are made this days, check out Tom McHale’s recent account of his visit to the Timney Factory in Scottsdale, Arizona. McHale explains how the triggers are designed and fabricated, and 20 high-rez photos illustrate the production process and machinery. If you have a passion for fabrication or machining, you’ll really enjoy McHale’s in-depth, 1600-word story.

Timney Triggers Factory Tom McHale Scottsdale Arizona CNC

CLICK HERE to read Timney Triggers Factory Tour Article by Tom McHale.

Timney Triggers Factory Tom McHale Scottsdale Arizona CNC

Timney Triggers Factory Tom McHale Scottsdale Arizona CNC

Tom McHale is the author of the Insanely Practical Guides book series that guides new and experienced shooters alike in a fun, approachable, and practical way. His books are available in print and eBook format on Amazon.com.

Permalink - Articles, Gunsmithing 1 Comment »
October 20th, 2014

Care and Feeding of the 50 BMG — A Look at Big Bore Shooting

A while back we published an Introduction to .50-Caliber Shooting authored by James Patterson. James has written a companion piece for Sinclair’s Reloading Press that covers the “care and feeding” of the big .50 Cal match rifles.

FCSA 50 Caliber 50 BMG

Owning and Feeding ‘The Big Bore’

Is The Challenge Of Big Bore Extreme Range Shooting And Hunting Right For You?
By James Patterson

Handling a 50 BMG
Is a 50 BMG caliber rifle difficult to shoot? Not at all. The relatively heavy weight of a standard rifle at 30 pounds or more combined with a very efficient muzzle brake makes it a pleasure to shoot. The typical recoil can be compared to a .243 rifle or a 12 gauge trap load. On the other hand, the burning of a typical load of 230 grains of powder combined with that muzzle brake makes the muzzle blast experience exhilarating. A first time shooter will fire, pause for a moment in awe at the muzzle blast, and then break out into what has become known as “The 50 caliber Grin”, almost impossible to wipe from ones face. My daughter started competing with the 50 BMG at 18 (115 lbs of tall skinny girl) and happily shoots 100+ rounds in the course of a match, her grin on the last round is as wide as on the first! Many members and competitors in the FCSA are women and many have distinguished themselves as excellent marksman having set world records on numerous occasions.

50 BMG

Cost of Big-Bore Shooting
Is owning and shooting a 50 BMG caliber rifle expensive? Relatively speaking yes, but one must put it into perspective. Rifles may run from $2500 to $7000, maybe even more for a top of the line custom rifle. A good scope will set you back $500 to $1500. And while excellent commercial ammo is available it runs from $3 to $5 a round. Most serious shooters start reloading for the rifle as soon as practical, not only for the economics of reloading but also for the ability to fine tune custom ammo for their specific rifle. It’s a very rare match that is won shooting commercial ammo. I recently compared the cost of my hobby — owning, shooting, and competing with the 50 BMG — with a friend whose hobby is snowmobiling. Factoring in the cost of equipment, licensing, gasoline, clothing, etc. it was soon obvious that my hobby was significantly less expensive than his.

50 BMG

FCSA 50 Caliber 50 BMG

Getting Started
FCSA 50 BMG Fifty Caliber Shooting AssociationSo how does one get started? You could do as I did, purchase a rifle not knowing what you were really getting into; or you could come out to a FCSA-sponsored event, shoot a number of different rifles, rub shoulders with those who have already taken the plunge, and see if this sport is right for you. While membership in the Fifty Caliber Shooters Association (FSCA) is required to compete at a FSCA event, membership is not required to come and experience first hand what is going on. If you have any inclination that you are interested in the extreme sport of long rang, big bore shooting then a year’s membership in the FCSA is only $60 ($20 for active duty military) a significant bargain if it helps you make just one well-informed equipment choice. In addition one of the primary functions of the FCSA is helping to identify active members near you who can help you understand just what is involved and help you ‘get your feet wet’ in this challenging sport.

FCSA 50 Caliber 50 BMG

Photos courtesy FCSA Photo Gallery.
Permalink - Articles, Competition 14 Comments »
October 19th, 2014

Hornady Handgun Safe Opens with RFID Signal

RAPID Safe Handgun box RFID radio IdentificationImagine this — your “home security” handgun is stored safely and securely near your bedside. But with the simple swipe of a keyfob, card, or wristband, you have instant access to the gun. Sound like science fiction? Well, this is real. Hornady’s new RAPID Safe uses RFID (Radio Frequency Identification) technology to allow instantaneous access to a firearm using either a special card, an RFID bracelet, or a special keyfob. In addition, the safe can be opened using a programmed keypad or a traditional key lock.

Brownells.com already has this new product in stock. Watch the video to see how the RAPID Safe works. The system runs with 110 volt AC power or internal battery pack. This short video shows various opening modes:

Open your safe in the blink of an eye. Simply place the included RFID bracelet, card, or key fob over the reader, and the RAPiD™ safe springs open to present your handgun.

RAPID Safe Handgun box RFID radio Identification

Permalink Handguns, New Product 2 Comments »
October 19th, 2014

Incoming! Video Shows “Target POV” of Rimfire Tracer Round

What would it be like to have a tracer round fly right past your eyeball? You’d never want to experience that in real life. But here’s an amazing short video that lets you see a “target-eye’s view” (POV) of an incoming tracer round. If you look carefully, you can actually see the bullet spinning (throwing off radial sparks) before it strikes the target.

Watch Incoming .22 LR Tracer Round:

YouTube shootist “22 Plinkster” placed a miniature video camera behind bullet-proof glass then fired a .22 LR tracer round right at the camera. With slo-mo playback, you can see the tracer leave the rifle barrel and fly directly at the camera, showing bright red sparks all the way. In this video, 22 Plinkster shoots a .22 LR tracer round at a camera protected by a layer of bulletproof glass. After the impact, there is a dark black crater left in the glass (lower photo).

Freeze Frame 1: Tracer Round Comin’ at You…
22 Plinkster tracer POV

Freeze Frame 2: Tracer Round Milli-Seconds from Impact
22 Plinkster tracer POV

Freeze Frame 3: Impact Crater on Bulletproof Glass Shielding Camera.
22 Plinkster tracer POV

Permalink - Videos, Bullets, Brass, Ammo Post comment »
October 19th, 2014

New American-Made Reproduction M1 Carbines

One of the CMP’s most popular competitions is the M1 Carbine Match. The little carbines are easy to hold and easy to shoot, with relatively low recoil compared to an M1 Garand or M1903 shooting the full-power .30-06 cartridge. Unfortunately, genuine GI-issue M1 Carbines are now hard to find at affordable prices. The CMP has announced: “CMP’S Carbine Inventory has been exhausted and we do not expect to receive any additional shipments.” Authentic, “all-original” M1 Carbines are going for $1500 to $1800.00 these days on Gunbroker.com.

CMP M1 Carbine Match at Western CMP Games
CMP M-1 Rimfire Carbine Citadel

New Production M1 Carbines
Thankfully, you can now get a brand new, American-made M1 Carbine clone for hundreds less than an old CMP rifle. MKS Supply is now offering American-made Inland Mfg. brand .30-Caliber M1 Carbines that look, feel, operate and shoot just like the originals.

CMP M-1 Rimfire Carbine Citadel

These made-in-the-USA, newly manufactured M1 Carbines are faithful copies of the original Inland Manufacturing carbines from the World War II era. (Inland was once a division of General Motors, but this is a new company with the same historic name.) They feature 1944-style peep sights and even include Arsenal cartouches on the stocks. All Inland M1 Carbine models come with a cloth sling and oiler resembling those given to GIs during WWII. MKS Supply will offer three (3) Inland M1 Carbine models:

    M1 1944 wood stocked original design without bayonet lug — MSRP $1049.00

    M1 1945 wood stocked original design with bayonet lug — MSRP $1049.00

    M1A1 Paratrooper original design with folding heavy wire buttstock — MSRP $1179.00

NOTE: The new Inland carbines are so precisely copied from the original specifications that the company marks the underside of the barrel and the inside of the stock of these current models to prevent potential fraudsters from passing these new carbines as mint WWII originals.

GunsAmerica.com reporters recently compared new Inland M1 Carbines side-by-side with original vintage M1 Carbines: “We had to get in close to tell the difference. Overall, the two examples we were able to handle looked great and held up when next to the originals. The stampings are even close to correct with a few minor differences that were chosen to stop the new Inlands from being mistaken for originals. Take a look at the photos and see for yourself.”

CLICK HERE for GunsAmerica Article.

CMP M-1 Rimfire Carbine Citadel

CMP M-1 Rimfire Carbine Citadel

CMP M1 Carbine Matches — Growing in Popularity
The CMP M1 Carbine Match is part of the CMP Games program that already includes Garand, Springfield and Vintage Military Rifle Matches. “As-issued” U. S. Military M1 Carbines are fired over a 45-shot course of fire at 100 yards on either the old military “A” target (or the SR target, if A targets prove to be too difficult to obtain). The course includes 5 sighters and 10 shots for record prone slow fire in 15 minutes, a 10-shot rapid fire prone series in 60 seconds, a 10-shot rapid fire sitting series in 60 seconds and 10 shots slow fire standing in 10 minutes. An M1 Carbine Match was fired during the National Matches in the early 1950s, and now is back. As a CMP Games event, it also can now be conducted as a CMP-sanctioned competition.

CMP M-1 carbine games

Permalink Competition, New Product 3 Comments »
October 19th, 2014

How Altitude and Air Pressure Influence Ballistics

Suunto AltimeterOne of our readers asked “What effect does altitude have on the flight of a bullet?” The simplistic answer is that, at higher altitudes, the air is thinner (lower density), so there is less drag on the bullet. This means that the amount of bullet drop is less at any given flight distance from the muzzle. Since the force of gravity is essentially constant on the earth’s surface (for practical purposes), the bullet’s downward acceleration doesn’t change, but a bullet launched at a higher altitude is able to fly slightly farther (in the thinner air) for every increment of downward movement. Effectively, the bullet behaves as if it has a higher ballistic coefficient.

Forum member Milanuk explains that the key factor is not altitude, but rather air pressure. Milanuk writes:

“In basic terms, as your altitude increases, the density of the air the bullet must travel through decreases, thereby reducing the drag on the bullet. Generally, the higher the altitude, the less the bullet will drop. For example, I shoot at a couple ranges here in the Pacific Northwest. Both are at 1000′ ASL or less. I’ll need about 29-30 MOA to get from 100 yard to 1000 yards with a Berger 155gr VLD @ 2960fps. By contrast, in Raton, NM, located at 6600′ ASL, I’ll only need about 24-25 MOA to do the same. That’s a significant difference.

Note that it is the barometric pressure that really matters, not simply the nominal altitude. The barometric pressure will indicate the reduced pressure from a higher altitude, but it will also show you the pressure changes as a front moves in, etc. which can play havoc w/ your calculated come-ups. Most altimeters are simply barometers that read in feet instead of inches of mercury.”

As Milanuk states, it is NOT altitude per se, but the LOCAL barometric pressure (sometimes called “station pressure”) that is key. The two atmospheric conditions that most effect bullet flight are air temperature, and barometric pressure. Normally, humidity has a negligible effect.

It’s important to remember that the barometric pressure reported on the radio (or internet) may be stated as a sea level equivalency. So in Denver (at 6,000 feet amsl), if the local pressure is 24″, the radio will report the barometric pressure to be 30″. If you do high altitude shooting at long range, bring along a Kestral, or remember to mentally correct the radio station’s pressure, by 1″ per 1,000 feet.”

You can do your own experimental calculations using JBM Online Ballistics (free to use). Here is an extreme example, with two printouts (generated with Point Blank software), one showing bullet trajectory at sea level (0′ altitude) and one at 20,000 feet. For demonstration sake, we assigned a low 0.2 BC to the bullet, with a velocity of 3000 fps.

Trajectory of Bullet fired at Sea Level

Trajectory of Bullet fired at 20,000 feet

if you want to learn more about all aspects of External Ballistics, ExteriorBallistics.com provides a variety of useful resources. In particular, on that site, Section 3.1 of the Sierra Manual is reprinted, covering Effects of Altitude and Atmospheric Pressure on bullet flight.

Permalink Tech Tip 5 Comments »